Punctuation: Dashes – Outschool
Punctuation: Dashes (and Parentheses) Lesson
1. What Dashes and Parentheses Do
Both dashes (—) and parentheses ( ) can set off nonessential information—extra details that can be removed without changing the core meaning of the sentence.
But they differ in tone and emphasis:
- Dashes = dramatic, emphasized interruption
- Parentheses = quieter, optional aside
2. When to Use Dashes
A. To set off an interruption in the middle of a sentence
Use two dashes if the extra info is in the middle:
The museum—recently expanded to three floors—hosts over 200,000 visitors a year.
You should be able to remove the part between the dashes and the sentence still works.
B. To introduce an explanation or example at the end
She knew exactly what the team needed—more practice.
This is similar to a colon, but more dramatic. Check the Punctuation Part 2 video for more information about the colon.
3. When to Use Parentheses
Parentheses hold less important, more “whispered” information.
A. To tuck away background information
The event (which had been postponed twice) finally took place.
B. To clarify small details
The recipe calls for saffron (about a teaspoon).
Parentheses should not be used for major sentence parts—the information must be truly optional.
4. ACT Tips
Tip 1: Keep the punctuation consistent.
If you begin a nonessential phrase with a dash, end it with a dash—not a comma.
Incorrect:
The hikers—exhausted after seven miles, stopped to rest.
Correct:
The hikers—exhausted after seven miles—stopped to rest.
Tip 2: Check if commas already work.
If the information is just a normal nonessential clause, commas are usually better.
Dashes are only correct if the writer intends strong emphasis.
Tip 3: If the tone is too strong or emotional, parentheses won’t fit.
Parentheses should never carry key or dramatic info.
5. Quick Examples
A. The winner—someone no one had expected—celebrated with the crowd.
✔ Dashes: surprising/emphatic info.
B. The tours (offered daily) last about two hours.
✔ Parentheses: small, side detail.
C. I finally understood the appeal of the sport—teamwork.
✔ Dash: explanation.